Why do people become politicians?

Why do people run for office? Is it because -- as I would guess -- of some psychological trauma they endured as children? Or do they possess a gene variant common in the Kennedy's?

A study in the American Political Science Review delves deeply into the subject concluding (shockingly) that people have different reasons:

The authors significantly revise existing methods of explaining decisions by lower-office holders to run for higher office. First, they distinguish between ambition formation and the decision to run itself, positing and finding that "progressive ambition" exists prior to a decision to run in a particular race. This distinction is important, the authors observe, because "the factors influencing the formation of ambition are fundamentally different from those driving the decision to run." In turn, the likelihood of entering a particular race depends on multiple calculations--including the long-run chances of winning, the marginal expected gain from the target office, and the marginal costs of running. The real strategic choice made by ambitious candidates, therefore, is not about whether to run as is widely assumed but rather about when to run.

Here is another choice quote that I found funny: "Professionalism enhances accountability in U.S. House campaigns by increasing the odds that a strong challenger will emerge from the state legislature when voters become dissatisfied with the status quo."

I agree totally -- professionalism does increase accountability. Now if we could only find some.